The Marauder pistol cannot be filled with CO2. Use only high-pressure air. Accurate, powerful, compact...it's everything you want from a high-quality PCP pistol. And, it doesn't come at a high price. For a real deal, check out our pre-packaged deals. Click on the AMMO link for a list of recommended pellets. The ACCESSORIES link has a list of targets, hand pumps and other gear you'll need. It includes both rifle and pistol scopes. A rifle scope can be used when you attach the included shoulder stock to your Marauder pistol. Shop related categories: pellet guns, pellet pistols